Caravan: In The Land Of Grey And Pink (1971)
Their peak was probably 1971's Grey and Pink, their third album. The highlight for me is the side-long "Nine Feet Underground" suite, satisfying the apparent requirement at the time that every progressive/art-rock band must release an album with at least one piece taking up an entire LP side (pushed to the extreme by Yes with the 4-song double-LP Tales from Topographic Oceans). The mainly instrumental medley (with a couple brief vocal interludes) is pretty jazzy and actually fairly compelling; perhaps not "Supper's Ready" or "Echoes," but certainly up there with "Atom Heart Mother" or anything that Yes or Tull ever pulled off.
And the shorter pieces are an interesting mix. Album opener "Golf Girl" is as close as the band would get to a pop song, a whimsical, twee charmer with a catchy hook; the pithy "Love To Love You" is even catchier and more straightforward, a concise blast of sweet simplicity. "Winter Wine" and the title track are on the folkier side, shades of bands like Tull and the Strawbs; though it's on these tracks in particular that Richard Sinclair's vocals, like those of many Canterbury Scene acts, are most stand-offish, not exactly my cup of (very British) tea.
While the vocals and the organ-driven sounds aren't always my thing, the album has a nice, entrancing vibe throughout, a little more on the jazz/folk side of the spectrum than the prog bands I prefer (like Crimson and Gabriel-era Genesis) but still charming.
Here's a live run through "Golf Girl" and "Winter Wine":